This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study is looking at the health effects of exposure to onsite wastewater systems [i.e. septic tanks] and sources of drinking water [wells]. Using a risk scoring system, three high-risk and three low-risk sites in three states will be selected for focused health studies for three years. The outcomes to be measured include: reported illnesses, drinking water contamination, viruses, and individual responses to infectious agents.